Tracing the Energetics and Evolution of Dust with Spitzer: a Chapter in the History of the Eagle Nebula

Abstract

The Spitzer GLIMPSE and MIPSGAL surveys have revealed a wealth of details of the Galactic plane. We use them to study the energetics and dust properties of M16, one of the best known SFR. We present MIPSGAL observations of M16 at 24 and 70 $\mu$m and combine them with previous IR data. The MIR image shows a shell inside the molecular borders of the nebula. The morphologies at 24 and 70 $\mu$m are different, and its color ratio is unusually warm. The FIR image resembles the one at 8 $\mu$m that enhances the molecular cloud. We measure IR SEDs within the shell and the PDRs. We use the DUSTEM model to fit the SEDs and constrain dust temperature, dust size distribution, and ISRF intensity relative to that provided by the star cluster NGC6611. Within the PDRs, the dust temperature, the dust size distribution, and the ISRF intensity are in agreement with expectations. Within the shell, the dust is hotter and an ISRF larger than that provided by NGC6611 is required. We quantify two solutions. (1) The size distribution of the dust in the shell is not that of interstellar dust. (2) The dust emission arises from a hot plasma where UV and collisions with electrons contribute to the heating. We suggest two interpretations for the shell. (1) The shell matter is supplied by photo-evaporative flows arising from dense gas exposed to ionized radiation. The flows renew the shell matter as it is pushed by the stellar winds. Within this scenario, we conclude that massive SFR such as M16 have a major impact on the carbon dust size distribution. The grinding of the carbon dust could result from shattering in collisions within shocks driven by the interaction between the winds and the shell. (2) We consider a scenario where the shell is a SNR. We would be witnessing a specific time in the evolution of the SNR where the plasma pressure and temperature would be such that the SNR cools through dust emission.

15 pages, 18 figures, (almost) accepted for publication in A&A

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Cited by in corpus (22)

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• Overview of the Massive Young Star-Forming Complex Study in Infrared and X-ray (MYStIX) Project
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• Ionization compression impact on dense gas distribution and star formation, Probability density functions around H ii regions as seen by Herschel
• Spitzer and Herschel multiwavelength characterization of the dust content of evolved HII regions
• A Multiwavelength Look at Galactic Massive Star Forming Regions
• The M16 molecular complex under the influence of NGC6611. Herschel's perspective of the heating effect on the Eagle Nebula
• Pillars and globules at the edges of H ii regions, Confronting Herschel observations and numerical simulations
• A multi-wavelength investigation of RCW175: an HII region harboring spinning dust emission
• Polycyclic aromatic hydrocarbons in spatially resolved extragalactic star forming complexes
• Radiation-pressure-driven dust waves inside bursting interstellar bubbles
• The PDR structure and kinematics around the compact HII regions S235A and S235C with [CII], [13CII], [OI] and HCO+ line profiles
• A bimodal dust grain distribution in the IC 434 HII region
• Chandra/ACIS-I study of the X-ray properties of the NGC 6611 and M16 stellar population
• The early evolution of young massive clusters: The kinematic history of NGC6611 / M16
• Dust Properties in HII Regions in M33
• The candidate luminous blue variable G79.29+0.46: a comprehensive study of its ejecta through a multiwavelength analysis
• Ultracompact H II Regions with Extended Emission: The Complete View
• SOFIA FEEDBACK Survey: The Pillars of Creation in [C II] and Molecular Lines
• Star formation history of Canis Major OB1 - II. A bimodal X-ray population revealed by XMM-Newton
• Wide field-of-view study of the Eagle Nebula with the Fourier transform imaging spectrograph SITELLE at CFHT
• Hadronic acceleration in the young star cluster NGC 6611 inside the M16 region unveiled by Fermi-LAT: constraints on the acceleration efficiency